Synthesis and Crystal Structure of a New Copper–PMIDA Compound (H4PMIDA=H2O3PCH2N(CH2CO2H)2)

A new Cu(II)PMIDA compound [Cu(H₂PMIDA)(phen)] 3H₂O (1) (H₄PMIDA = H₂O₃PCH₂N (CH₂CO₂H)₂,phen = 1,10-phenanthroline) has been successfully synthesized and structurally characterized. In complex 1, Cu (II) is six coordinated by chelation in a tetradentate fashion by a PMIDA ligand and by two N atoms of a phen ligand. Every phen–Cu(II)–PMIDA group connects with each other via a hydrogen bond and the edge-to-face -stacking interaction. Complex 1 crystallized in triclinic P-1 with cell dimensions of a = 7.5817(6) Å, b = 10.6980(8) Å, c = 13.1852(10) Å, =82.350(2)°, = 84.151(2)°, =78.4250(2), V= 1035.25(14) ų, Z = 2, Dc = 1.677 Mg/m³.     

Aerobic oxidation of benzylic aldehydes to acids catalyzed by iron （Ⅲ） meso-tetraphenylporphyrin chloride under ambient conditions

Highly efficient aerobic oxidation of benzylic aldehydes to the corresponding acids catalyzed by iron (Ⅲ) meso-tetraphe- nylporphyrin chloride (Fe(TPP)Cl) under ambient conditions was developed.The catalyst has been proved to be an excellent catalyst for the system in the presence of molecular oxygen and isobutryaldehyde at room temperature.     

A novel approach for characterizing protein ligand complexes: molecular basis for specificity of small-molecule Bcl-2 inhibitors

The increasing diversity of small molecule libraries has been an important source for the development of new drugs and, more recently, for unraveling the mechanisms of cellular events-a process termed chemical genetics.(1) Unfortunately, the majority of currently available compounds are mechanism-based enzyme inhibitors, whereas most of cellular activity regulation proceeds on the level of protein-protein interactions. Hence, the development of small molecule inhibitors of protein-protein interactions is important. When screening compound libraries, low-micromolar inhibitors of protein interactions can be routinely found. The enhancement of affinities and rationalization of the binding mechanism require structural information about the protein-ligand complexes. Crystallization of low-affinity complexes is difficult, and their NMR analysis suffers from exchange broadening, which limits the number of obtainable intermolecular constraints. Here we present a novel method of ligand validation and optimization, which is based on the combination of structural and computational approaches. We successfully used this method to analyze the basis for structure-activity relationships of previously selected (2) small molecule inhibitors of the antiapoptotic protein Bcl-xL and identified new members of this inhibitor family.     

A FLUORESCENCE STUDY OF THE BINDING OF HOECHST 33258 and DAPI TO HALOGENATED DNAs

We have studied the time-resolved and the steady-state fluorescence of the DNA groove binders 4',6-diamidino-2-phenylindole (DAPI) and Hoechst 33258 with the double stranded DNAs poly(dA-dU) and poly(dI-dC) and their halogenated analogs, poly(dA-I5dU) and poly(dI-Br5dC). These studies were prompted by earlier observations that steady-state fluorescence of Hoechst 33258 is quenched on binding to halogenated DNAs (presumably due to an intermolecular heavy atom effect involving the halogen atom in the major groove), and recent studies which clearly point to a binding-site in the minor groove of DNA. Measurements of the time resolved fluorescence decay demonstrate that the fluorescence of Hoechst 33258 is quenched on binding to the halogenated DNAs, in agreement with previous observations. However, quenching studies carried out using the free halogenated bases IdUrd and BrdCyd in solution yielded bimolecular rate constants more than one order of magnitude larger than those expected for an intermolecular heavy atom effect. Moreover, the quenching of the Hoechst 33258 fluorescence was accompanied by an accelerated photochemical destruction of Hoechst 33258. We therefore conclude that the fluorescence quenching observed with halogenated DNAs is probably due to a photochemical reaction involving Hoechst 33258, rather than direct contact of Hoechst 33258 with the halogen substituents in the major groove of the DNA. The fluorescence decay measurements however, do provide clear evidence for at least two different modes of binding. Taking into account the alternating sequences used in this study and the possibility of two different conformations for bound dye, at least four different modes of binding are plausible. Our present data do not allow us to distinguish between these alternatives. The time-resolved fluorescence decays and fluorescence quantum yields of DAPI are not affected by the presence of the heavy atom substituents in the DNA major groove. Based on this observation and earlier reports that DAPI binds in one of the DNA grooves, we conclude that the high affinity sites for DAPI on DNA are located in the minor groove.     

A novel sensitive non-enzymatic glucose sensor

Cu nanoclusters were electrochemically deposited on the film of a Nafion-solubilized multi-wall carbon nanotubes (CNTs) modified glassy carbon electrode (CNTs-GCE), which fabricated a Cu-CNTs composite sensor (Cu-CNTs-GCE) to detect glucose with non-enzyme. The linear range is 7.0×10-7 to 3.5×10-3 mol/L with a high sensitivity of 17.76μA/(mmol L), with a low detection limit 2.1×10-7 mol/L, fast response time (within 5 s), good reproducibility and stability.     

微量元素在补益中药中的作用

从中药补气药，补阳药，补血药，补阴药等四个方面阐述了微量元素在补益中药中的作用。     

强偶合体系异核二维相关NMR谱解析

本文对异核二维相关NMR谱中强偶合的影响进行了分析,给出量子力学的定量描述。用所建立的计算机NMR谱解析系统模拟了AB(X)自旋体系以及蔗糖的异核二维相关谱。     

用非等温DSC估算3,4-双(4’-硝基呋咱-3’-基)-2-氧化呋咱(BNFOF)放热自催化分解反应的热爆炸临界温升速率和动力学参数

A method of estimating the kinetic parameters and the critical rate of temperature rise in the thermal explosion for the autocatalytic decomposition of 3,4-bis（4＇-nitrofurazan-3＇-yl）-2-oxofurazan （BNFOF） with non-isothermal differential scanning calorimetry （DSC） was presented. The rate equation for the decomposition of BNFOF was cstablished, and information was obtained on the rate of temperature increase in BNFOF when the empiric-order autocatalytic decomposition was converted into thermal explosion.     

Preparation and characterization of nanotube Li-Ti-O by molten salt method

Nanotube Li-Ti-O compound with high surface (198.6 m²·g⁻¹) was prepared by a method involving the treatment of nanotube Na₂Ti₂O₅·H₂O in molten LiNO₃ and characterization by means of transmission electron microscopy (TEM), energy-dispersive spectra (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and thermogravimetry-differential thermal analysis (TG/DTG). Results show that the nanotube Li-Ti-O compound prepared by this method involves two crystal phases: spinel Li₂Ti₂O₄ and anatase Li_xTiO₂ (x < 0.1). Li⁺ exhibits different Li1s binding energy in the two crystal phases. In ambient air, the Li-Ti-O compound adsorbs water easily, and the chemically adsorbed water is difficult to remove below 400°C. Translated from Chinese Journal of Inorganic Chemistry, 2006, 22(12): 2135–2139 [译自: 无机化学学报]